“…The anatomy of two extant xiphosurids, the American horseshoe crab— Limulus polyphemus ( Linnaeus, 1758 )—and the mangrove horseshoe crab— Carcinoscorpius rotundicauda ( Latreille, 1802 )—has been documented using micro-CT ( Göpel & Wirkner, 2015 ; Bicknell et al, 2018a ; Bicknell et al, 2018b ; Bicknell et al, 2021b ; Bicknell, Melzer & Schmidt, 2021 ). Magnetic resonance imaging has also been used in studies of the Japanese horseshoe crab— Tachypleus tridentatus ( Leach, 1819 ) ( Kutara, Une & Fujita, 2019 ; Yuen, Kwok & Kim, 2019 ). However, as Bicknell & Pates (2020) highlighted, there are over 80 extinct xiphosurids that have not been documented or rendered in 3D and most 3D data collected from fossil xiphosurids have been surface scans ( Schimpf et al, 2017 ), with other applications including stereo imaging ( Haug et al, 2012 ; Haug & Rötzer, 2018 ; Haug & Haug, 2020 ).…”